Today, the Intergovernmental Panel on Climate Change (IPCC) has released a major study (pdf) on the likely impact of climate change on specific geographical regions.

The report delivers a wake-up call about the impact upon wildlife, water and food security, and the overall effect upon national economies and society at large. Its authors conclude that significant further warming can be expected in the tropics, and that droughts will worsen in much of the world, including Australia, the southern United States and southern Europe. Meanwhile, other countries, including those in Scandinavia and Canada, can anticipate more rain and snow.

These forecasts, which collectively point to potentially devastating impacts – if trends are left unchecked – have been given enhanced credibility by the fact that the world is already seeing clear signs of climate change's accelerating impacts. In recent months, for instance, parts of Australia have experienced their worst ever drought while there has been extreme, prolonged rainfall, together with river and coastal flooding in Asia across to Europe – among the worst on record.

The central message for politicians and policymakers is that "the worst is yet to come" but, if treated fast, the greatest risks can be avoided. Although some irreversible change may now be inevitable, there is still time for the international community to act to prevent what scientists consider to be "dangerous climate change", where global average temperature rise is limited to no more than 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels.

One exciting development that offers real hope is that, in contrast to the slow pace of international negotiations to combat climate change, national legislation to tackle climate change is advancing at a startling rate. Remarkably, by the end of 2013, almost 500 climate-related laws had been passed in 66 countries covering almost 90% of global greenhouse gases released by human activities.

This surprising legislative momentum is happening across all continents. And, encouragingly, this progress is being led by the big emerging and developing countries, such as China and Mexico, which together will represent 8 billion of the projected 9 billion people on Earth in 2050.

These are the core findings of the latest Globe climate legislation study, released in February, which is the most comprehensive audit yet of the extent and breadth of the emerging legislative response to climate change. While optimistic, the report is honest. These laws are not yet enough to limit global average temperature rise to 2 degrees Celsius above pre-industrial levels. However, they are putting into place the legal frameworks necessary to measure, report, verify and manage greenhouse gas emissions – the cause of man-made climate change.

And as the formal UN negotiations move towards Paris in 2015, the scheduled conclusion of negotiations on a post-2020 framework, legislation is creating a strong foundation on which a post-2020 global agreement can be built. It is increasingly clear that not only is the agreement in Paris dependent on national legislation in place in advance, implementation of the Paris agreement will only be effective through national laws, overseen by well-informed legislators from all sides of the political spectrum.

The process to pass legislation begins with building a common understanding among the major political parties of the risks and opportunities presented by climate change, which is the foundation for developing a nationally appropriate legislative response. This response should both mitigate the risks by cost-effectively reducing emissions of greenhouse gases, maximise the opportunities by supporting the growth of new low-carbon industries and improve the economy's resilience to the likely impacts of climate change.

Countries learn from the experience of others and we are seeing legislators taking the laws of countries with similar economic characteristics and adapting them to their own national circumstances. And the process of understanding the risks and opportunities for the national economy help to strengthen legislators ability to effectively hold their governments to account on the commitments they make, both domestically and in the international negotiations.

A national commitment or contribution put forward at the UN will only be credible – and durable beyond the next set of elections in a country – if it is backed up by national legislation, supported by cross-party legislators, that puts in place a credible set of policies and measures to ensure effective implementation.

Of course, the role of legislators does not end when legislation is passed. It is one thing to pass legislation and another to implement it. That is why Globe is also equipping legislators to be as effective as possible in holding their governments to account.

The predictions of the latest IPCC report must motivate governments to immediately prioritise supporting the implementation of national legislation between now and 2015. We need to see consensus and policy at national level if we are ever to get agreement in Paris in 2015.

Adam Matthews is secretary-general in London and Terry Townshend is head of policy at Globe International in Beijing. Follow @GLOBE_intl on Twitter

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